Identification of Distinct Endosymbionts of Whiteflies-infesting Cassava (Manihot esculenta Crantz), using Diagnostic PCR and Sanger Sequencing

Abstract

The study was conducted during March–December 2021 in  Thiruvananthapuram, Kerala for the identification of distinct endosymbionts of cassava whiteflies (Bemisia tabaci (Gennadius) and Aleurodicus dispersus (Russell). Endosymbiotic bacteria found in whiteflies have been reported to interact and provide specific advantages to the hosts and they can be one of the reasons for whiteflies’ insecticidal resistance. In the present study, endosymbiotic bacteria were isolated from the insects, allowed to grow in media after insecticidal treatments and after observing colony morphology, distinct bacterial colonies were sub-cultured and selected for further molecular identification procedures. PCR analysis was carried out for bacteria using 16S rRNA primer, with an annealing temperature of 49°C and yielded fragments at 1500 bp. Based on the sequencing report the observations were that the culturable endosymbionts Providencia present in B. tabaci is resistant to chlorpyrifos and Paenibacillus alvei present in A. dispersus is resistant to imidacloprid and chlorpyrifos. Clostridium senegalens and Acinetobacter are found in control populations of Bemisia and Aleurodicus respectively.The sequences were submitted to NCBI and the accession numbers obtained were OP303253, OP303256, OP303254 and OP295124. Also, through diagnostic PCR using specific bacterial primers, presence of Portiera aleyrodidarum at fragment length of 1000 bp and Wolbachia at 650 bp in B. tabaci and Rickettsia at fragment length of 800 bp in A. dispersus are confirmed. The study could identify bacteria which are decisive in their presence and activity in whiteflies.